Manufacture of stranded electric multicore cables



Nov. 20, 1934. A. ROHS- 1,981,390

MANUFACTURE OF" STRANDED ELECTRIC MULTICORE CABLES Filed? Feb. 1:5, 1955 I NVQNTOR mwm Patented Nov. 20, 1934 UNITED STA TES PATENT OFFICE MANUFACTURE OF STRANDED ELECTRIC MULTICORE CABLES many Application February 13, 1933, Serial No. 656,635 In Czechoslovakia February 1'1, 1932 (Cl. nv -zo) 3 Claims.

'I'his'invention relates to a method of and an apparatus for the manufacture of a stranded conductor of non-circular cross-section for multicore cables, the longitudinal axis of which con- 5 ductor lies in a straight line and its non-circular cross-section makes one revolution about thesaid axis over a distance approximately equal to the pitch with which the strand is to be cabled, after it has been insulated. It has previously been proposed first of all to manufacture non-circular stranded conductors with edges parallel to the longitudinal axis of the conductor and then continuously to twist such conductors around the According to one known method, a conductor core of the desired outer non-circular shape is laid on a stranding machine from individual wires and the said wires are stranded with a pitch which isequal to the winding length of a single insulated conductor when laid in the completed cable. ()ver such a core one or more covering layers are then laid. The die of the stranding machine is rotated at the same speed and in the same direction of rotation as the stranding cage carrying the wires-of the core.

As the manufacture of a conductor according to this method requires a separate stranding cage for the wires of the core, which stranding cage generally rotates ata different speed and in a different direction of rotation from, the stranding machine which is already available in the works for the manufacture of circular strands cannot be used for the manufacture of the stranded conductors which come into question without any alteration.

A method is already known which avoids this disadvantage. This method consists in this that an ordinary conductor strand of circular crosssection is first of all produced on a normal stranding machine serving for the manufacture of circular strands and-the said strand is then formed with the required non-circular cross- 7 section and at the same time pre-formed in the desired helical shape by means of a hammering device rotating around the longitudinal axis of ing cage for the covering wires, 9. normal strandthe conductor. This method has, however, the disadvantage that the arrangement of the rotating pre-forming device is too complicated and expensive owing to the provision of the individual hammers.

The above-mentioned disadvantages can be avoided by the present invention.

It is known to manufacture a stranded conductor of non-circular cross-section for electric multi-core cables the longitudinal axis of the conductor of which lies in a straight line, and the edges of which conductor are parallel-to its axis and the filling factor is highly increased, by first manufacturing a conductor strand, the longitudinal axis of which lies in a straight line and the cross-section of which is of circular form, on a normal stranding machine, the said strand being then guided between the rollers of a rolling apparatus, the passage between the rollers of which have the desired non-circular cross-section, and being thereby rolled to the desired noncircular cross-section, the axis of the conductor retaining its straight condition during the rolling process and the filling factor of the stranded conductor being thereby increased. According to the Present invention the conductor the cross-section of which is of circular form, after leaving the normal stranding machine,v is guided between the rollers of a rolling apparatus, the rollers being rotated around the longitudinal axis of the conductor for the purpose of rolling the said strand to the desired non-circular cross-section, and simultaneously therewith to a revolution of the cross-section, the non-circular cross-section making one revolution about the said axis in a distance approximately equal to the pitch with which the strand is to be cabled, and the axis of the conductor retaining its straight condition during the rolling process. The object of the invention consists in that the known methodof rolling a conductor strand, the cross-section of which is circular, to a strand of non-circular cross-section having a highly. increased filling factor is adapted to the manufacture of a conductor strand the non-circular cross-section of which is twisted around the axis of the strand.

The ratio of the number of revolutions of the rolling apparatus which rotates around the longitudinal axis of the conductor to the take-off speed of the take-off disc determines the desired revolution of the cross-section.

The apparatus for the manufacture of a stranded conductor of non-circular cross-section for multi-core cables consists of a stationary stranding die having a circular passage to strand rotating around the longitudinal axis of the stranded conductor. In a modification of the apparatus according to the invention there is provided a die having a non-circular cross-section which corresponds to the non-circular crosssection of the stranded conductor for the purpose of guiding the stranded conductor to ;the capstan.

Use may'also be made of two rotating rolling devices arranged one behind the other, one of which may be used for preliminarily-rolling the conductor and the other one for completing its rolling.

The manufacture of the conductor strands of circular cross-section and the rolling. may be eifected in one single or in two separate operations. In the first case, the rolling apparatus is built in the stranding machine and the rolling apparatus may be driven from any shaft of the stranding machine. It is not, however, absolutely necessary that the rolling apparatus should be built in the stranding machine; the said apparatus may be mounted separately from the stranding machine. In this case the conductor strand of circular cross-section is first of all produced on the stranding machine and is then pulled in l a separate operation through the rolling appara- The accompanying drawing illustrates, by way of example, one form of construction of the arrangement used for carrying the invention into effect, the arrangement being shown in conjunction with a stranding machine.

The wires 1 which leave the drums of the stranding machine used for the manufacture of strands of circular cross-section run into a fixed stranding die 2 wherein the wires are stranded together into a stranded conductor of circular cross-section. The stranded conductor leaving the stranding die goes to a rolling apparatus 3 which rotates around the longitudinalaxis of the conductor and which imparts to the conductor of circular cross-section the desired cross-section and at the same time the desiredhelical form.

The non-circular stranded conductor which has been rolled into a helical form then passes to a guide die, which is shaped to a form correspond,- ing to the cross-section of the conductor, the said guide die consisting of two or moreradially adjustable rollers 4 and rotating at, the same speed and in the same oirection of rotation as the rolling apparatus 3. The die rollers 4 may also be provided directly on the rolling apparatus 3. The completed conductor is drawn off by the draw-off disc 5.

thesaid axis over a distance approximately equal to the pitch with which the strand is to be cabled, consisting of a stationary stranding die having a circular passage to strand a number of wires to a stranded conductor the longitudinal axis of which lies in a straight line and the cross-section of which is circular, in combination with a rolling apparatus, the rollers of which include a passage having the desired non-circular cross-section and is capable of rotating around the longitudinal axis of the stranded conductor for the purpose of rolling the said stranded conductor of circular cross-section to a stranded conductor having the desired non-circular cross-section and simultaneously therewith the desired revolution of the cross-section, the axis of the conductor retaining its straight condition during the rolling process.

2. An apparatus for the manufacture of a stranded conductor of non-circular cross-section for multi-core cables, the longitudinal axis of the conductor lying in a straight line arid its noncircular cross-section making one revolution about the said axis over a distance approximately equal to the pitch with which the strand is to be cabled, consisting of a stationary stranding die having a circular passage to strand a number of wires to a stranded conductor, the longitudinal axis of which lies in a straight line and the crosssection of which is circular, in combination with a rolling apparatus, the rollers of which include a passage having the desired non-circular crosssection and is capable of rotating around the longitudinal axis of the stranded conductor for the purpose of rolling the said stranded conductor of circular cross-section to a stranded conductor having the desired non-circular cross-section and simultaneously therewith the desired revolution of the cross-section, the axis of the conductor retaining its straight condition during the rolling process, and further in combination with a die having a non-circular cross-section which correconsisting in first manufacturing a conductor strand, the longitudinal axis of which lies in a straight line and the cross-section of which is of circular form, on a normal stranding machine serving for the manufacture of the said strand, the said strand being then guided between the rollers of a rolling apparatus, the passage between the rollers having the desired non-circular crosssection andthe rollers being rotated around the longitudinal axis of the conductor for the purpose of rolling the said strand to the desired noncircular cross-section and simultaneously therewith to a revolution of the cross-section, the noncircular cross-section making one revolution about the said axis in a distance approximately equal to the pitch with which the strand is to be cabled. 14..

and the axis of the conductor retaining its straight condition during the rolling process. 

